(Applicant's Abstract) The primary function of the Human Studies Core is to support individual research projects within the SCOR by providing the personnel, facilities, and structure to accomplish the following specific aims: (1) To generate and maintain an asthma patient database; (2) To provide a central facility using uniform criteria for recruiting and screening patients for clinical studies; (3) To provide a central facility for performing all bronchoscopic and airway challenge procedures; (4) To coordinate the distribution of patient specimens for analysis in individual projects; (5) To provide quality control and proper patient safeguards in the acquisition of patient specimens; and (6) To provide expertise in statistical analysis, study design, and data management.